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Jeff Smith

K's GWR 63xx - New P4 chassis options, suggestions

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That is looking very promising, Geoff.

 

I have a rather old 43xx Mainline body, which will partner a Perseverance chassis at some point in the future. This thread has been incredibly useful. 

 

Best wishes,

 

Nick.

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Nick, how old is the Percy chassis, I don't think they are still available?

 

This Comet chassis is the first fully sprung one I've tried.  I wanted to drive the centre axle so springing seemed a good solution.  My only real concern is whether it will sit at the right height!

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Whatever chassis is used I do hope there is more room between the slidebars than on the old Whitbourne Models chassis I put under a Mainline 43xx a couple of years ago. An older design from the 80's I eventually ditched the central beam compensation but really struggled to get enough clearance on the front drivers even with recessed crankpins and no sideplay because it used scale width slidebars. This was to P4 but I guess the issue would be the same with EM.

 

Izzy

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The Comet etched tender chassis has rear guard irons.  The tender on 5322 at Didcot has no guard irons and other 3500 gal tenders don't seem to have either.  It's possible that the irons are for the LMS usage as the kit does contain alternative LMS brake shoes.

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Having installed the front and rear drivers and pony truck to do a height check it appeared to be sitting too high on the chassis.  However the buffer beam And footplate are at the correct height.....

The visual problem seems to be the splashers which are too large.  I assume this was necessary in white metal to allow for casting thickness.....A very approximate eyeball measurement compared to the frame diagram in GWRJ No19 puts the splasher at about 2mm too high and 3 or 4 mm too long.

I think I will just have to live with it as it would be a major carve up to change....

 

 

E098E34C-358F-4AED-8548-5AC8513C28EA.jpeg

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The splashers were designed to accommodate standard 00 wheel sets which would have oversize flanges and also be over wide . It is possible to fabricate scale splashers from plastic or metal, the trick is the carving away of the old ones.:unsure: If you have a Dremel or similar rotary tool and patience it can be done, just go easy and don’t try to carve too much at one go.

 

Cheers,

 

David

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Posted (edited)

I still can separate the boiler and footplate so I'll give it some thought, and I do have a Dremel....... It would improve the appearance...

Edited by Jeff Smith

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On 30/04/2020 at 10:53, Izzy said:

Whatever chassis is used I do hope there is more room between the slidebars than on the old Whitbourne Models chassis I put under a Mainline 43xx a couple of years ago. An older design from the 80's I eventually ditched the central beam compensation but really struggled to get enough clearance on the front drivers even with recessed crankpins and no sideplay because it used scale width slidebars. This was to P4 but I guess the issue would be the same with EM.

 

Izzy

Well, having now assembled the centre driver and quartered the wheels.  I filed the front driver nuts as much as I dare and guess what the nuts foul the crossheads.....

 

The solution I hope will be to move the cylinders out about a mm each side by cutting the stretcher and re-attaching to a filler piece (modified spare frame spacer) 2mm further apart.

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Yes, with these kind of situations recessed crankpins are a must by default. The danger with moving the cylinders out is that they will clout platforms if everything is done to scale dimensions. And with the 43xx the tops of them should fit flush with the outside of the footplate. Otherwise they will stand proud and look wrong. If you have any you could try using Gibson crankpins put on backwards. Cut a small slot across the back face to screw them in, and leave the normal bush off. Then cryno them in place when all is satisfactory. This assumes Gibson wheels. An alternative is to just use a countersunk screw fitted from the front. As a crankpin and retainer combined. Looks crap but isn’t seen behind the cylinders/motion when it’s fitted. If Sharmans a bit of bodgery to fit them is needed. Might be better than widening the cylinders. Could try it first anyway just to see.
 

Izzy

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I have not made the cut yet but the top edge of the cylinder should be flush with the footplate as in the protoype when I've made the change - I did a photo survey of 5322 at Didcot a couple of years ago.

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Ah, perhaps they are under scale width as is, that’s handy. Hope it works out.

 

Izzy

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Posted (edited)

Whenever I used Laminated rods where the leading crankpin runs behind the crosshead my trick is to snip  the front boss off the overlay and retain to the the pin with a 14BA brass washer. This makes that area no thicker than the remainder of the rod. That and file as much as I dare from the rear of the crosshead, Much easier than mucking about with cylinders and risking going out of gauge. HTH

Steve

 

Edited by Carnforth

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Crankpins have been an issue on some Wills/Southeastern Finecast kits I am building in EM gauge. Note to self "file back the step support bars before fitting". This is on inside cylinder locos !!!

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The GWR frame drawing shows the measurement over the cylinders as 8'11" , just one inch inside the loading gauge which according to the Scalefour digest sheets is 36mm in 4mm scale.  And guess what, the Comet cylinders are 36mm!  Widening them was a no-go.

 

My solution was to crank the slide bars right at the cylinders to give the extra mm and to file away the inside faces of the crossheads as much as possible.  It's close but seems to work.  The slide bars are still parallel to the wheels and the slight crank is hardly noticeable!

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I seem to remember that certain outside cylinder locos were banned from some routes because they tore up the platforms, or perhaps the platforms tore the cylinders. This was in BR days, exGWR locos on Midland region lines. Something like that anyway.

 

Izzy

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10 hours ago, Izzy said:

I seem to remember that certain outside cylinder locos were banned from some routes because they tore up the platforms, or perhaps the platforms tore the cylinders. This was in BR days, exGWR locos on Midland region lines. Something like that anyway.

 

Izzy

 

GW locos on none GW lines.

 

 

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On 11/06/2020 at 08:00, Siberian Snooper said:

 

GW locos on none GW lines.

 

 

Like the Grange that made it to Huddersfield, ripping away at platforms as it made its way up from Sheffield.  The trip back must have been interesting, I think it went back via Manchester.

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So the next problem, having assembled the Comet tender chassis was to attach it to the tender body.  The chassis was built using the suggested one rigid axle (I chose the leading one) with the other two on a simple central compensation beam.  The central beam pivot holes were provided as were suitable slots in the spacers.  Parts for the beam were not included in the kit.  I used some brass wire and tube from my materials box.  I also had to file off some of the pin-point boss material from inside the axle boxes.

 

I used two of the threaded K's frame spacers bolted and soldered through the top of the tender with headless bolts soldered into the other ends.  This gave me some adjustment for ride height.  Luck was on my side as the last picture shows....

 

IMG_0444.jpg.427a1f4da194bd7757359676274c1972.jpg

IMG_0445.JPG.1008984e8cc8b00320829ba02955b54c.JPGIMG_0446.JPG.59d69a7321d6ccc5d3b08489eb8727ae.JPGIMG_0457.JPG.c7a1f6f86e407265e6425a4f3eb9fa31.JPG

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Looks very good. I have a suggestion, could you fit a piece of tube transversely across the tender chassis to match the vacuum reservoir end castings between the front and middle axle boxes? At least I think that's what it was, I don't have my GW loco book to hand to check.

 

 

 

 

 

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I turned out my 63xx set of castings yesterday during a bit of a 'rearrangment' of my stash.  It's all there and I do have a Comet 63xx chassis and tender kit - but I bought it to fit under a Bachmann loco I obtained at a very silly price last year at Wakefield show.  When I bought it I went straight round to the Wizard stand before I changed my mind!  However, reading this has set the old grey cells circulating as I do like to make proverbial silk purses out of sow's ears!

 

Regarding the crank pin/crosshead potential problem (especially in P4) I either leave off the front end of the 'upper' layer of the laminated rods or drill/enlarge the hole out to clear a 14BA threaded top hat bush that I turn up myself and screw in from the front with a very thin minimal flange.  I started doing this when I realised that not all the Gibson 'nuts' have the thread positioned centrally in the turning.  This creates a sort of 'cam' effect as it rotates and can cause tight spots.  So far I've only done this on outside cylinder industrial tanks but I expect the principal to be the same on a larger loco.

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An update.  Still awaiting a fallplate, pickups, backhead painting and a coal load.  But looking quite good.  Green is Railmatch GWR post 1928 acrylic, goes on really well with a soft brush, three coats over aerosol matt grey.  Finished with Testors matt acrylic.  Still not sure about the Humbrol acrylic buffer beam red colour but easy to use.  Black is Testors acrylic flat - I really want to like Vallejo but for me Testors (Modelmaster) gives a tougher finish.

 

IMG_0550.jpg.a9755a800354437acaea47d80f627bd3.jpgIMG_0551.jpg.eeeea504941a5aec50961ec5cd22abd8.jpg

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There is another 6363 available on eBay, built in 1972, what a coincidence!

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Very nice - is there any particular reason why it has a  BR smokebox plate fitted? I know some tenders lasted with the letters 'GWR' on the side (Frilsham Manor had on into the '60s) but did 6363 keep one with a Shirtbutton?

 

Adam

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I would say it is probably a mistake......  I was basing the model on a photo of 6363 taken in Sept 1949. however you cannot see the tender markings or the main colour as it is monochrome.

 

I'll do a little research and either remove the BR number plate and add a buffer beam number, or assuming the loco did not get black livery, change the tender marking.

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